How do you long divide #n^2-11n-26 div n+2#?

1 Answer
Nov 10, 2015

#(n^2-11n-26) div (n+2) = (n-13)#
(see explanation for details of long polynomial division)

Explanation:

Set up as if doing a standard long division
#{: (,,"-----","-----","-----"), (n+2,")",n^2,-11n,-26) :}#

The leading term of the divisor #color(green)(n)# divides into the leading term of the dividend #color(blue)(n^2)#, #color(red)(n)# times

#{: (,,color(red)(n),,), (,,"-----","-----","-----"), (color(green)(n)+2,")",color(blue)(n^2),-11n,-26) :}#

Multiply the divisor #color(green)(n+2)# by the term just written in the quotient (#color(red)(n)#) giving a product of #color(cyan)(n^2+2n)#
and subtract this product from the dividend giving a difference of #color(blue)(-13n)# and "bring down the next term, #color(orange)(-26)#
#{: (,,color(red)(n),,), (,,"-----","-----","-----"), (color(green)(n+2),")",n^2,-11n,-26), (,,color(cyan)(n^2),color(cyan)(+2n),), (,,"-----","-----",), (,,,color(blue)(-13n),color(orange)(-26)) :}#

Repeat this process to get:

#{: (,,n,-13,), (,,"-----","-----","-----"), (n+2,")",n^2,-11n,-26), (,,n^2,+2n,), (,,"-----","-----",), (,,,-13n,-26), (,,,-13n,-26), (,,,"-----","-----"), (,,,,0) :}#